The present invention is an improvement in intraocular lenses for implantation into the human eye, replacing a cataractus natural lens. More specifically the present invention is an iris-plane intra-ocular lens which overcomes the problem of severe warping (sometimes called "basket-weaving") of the iris at the pupillary margin.
The problem of restoring useful vision to a human eye whose cataractus natural lens has been removed, i.e., an aphakic eye, has been with us for as long as cataract surgery has been performed. Various solutions for restoring aphakic vision have been attempted, and such solutions have included bulky thick spectacle lenses and contact lenses. Another solution has been the intra-ocular implantation of a manmade lens to replace the removed natural lens. A variety of such intra-ocular lenses have been used with various degrees of success and failure. Among known intra-ocular lenses are the Choyce lens, the Binkhorst 4-Loop Intra-Capsular lens, the Medallion Intra-Capsular lens, the 2-Loop Binkhorst Extra-Capsular lens, the 2-Loop Binkhorst with Iris Clip Extra-Capsular lens, the 4-Loop Binkhorst Maltese Cross lens, the Copeland and New Copeland lenses, the Federov Russian lens, and the new Posterior Chamber lens.
Iris plane intra-ocular lenses such as the Copeland lens have been known for some time, but they still cause severe warping or basket-weaving of the iris at the pupillary margin when implanted in the human eye. Such severe warping in turn often causes post-implant complications such as iritis, cystoid macular edema, and unnecessary glare.